Wireless network communication system and method

ABSTRACT

A communication system comprising one or more wireless stations programmed to await for an authorizing signal to initiate wireless communications with a network controller or access point. The network controller maintains identification information in different queues, and polls stations from those queues. The wireless station identification information may be moved between the different queues in response to wireless station activity. Between polling, each mobile station aggregates data for the next opportunity to transmit. Multi-polling may be employed such that more than a single station is polled at a time. Polling is accomplished by polling one of the more stations from each queue having the effect that stations in one queue are polled more often than those in another queue. If a lesser active station becomes active, it may be moved into the shorter queue and consequently will be polled more often.

PRIORITY

This application claims the benefit of U.S. patent application Ser. No.12/534,120 entitled “Wireless Network Communication System and Method”by the same inventors filed on Aug. 1, 2009 which is incorporated byreference as if fully set forth herein.

BACKGROUND

The present invention relates generally to a system and method forwireless communications and more particularly to a method for wirelessdigital communications between multiple nodes located at a distance fromeach other.

In wireless communication, devices send and receive messages (dataflows) through radio or other means without being physically connected.Wireless devices may include portable computers, cellular telephones,personal digital assistants (PDAs), communications equipment, locationsensors and the like. Mobile processing devices with wirelesscommunication capability can be coupled to a computer network, such asthe Internet or the World Wide Web. The IEEE 802.11 standards (includingIEEE 802.11a, IEEE 802.11b, IEEE 802.11g, and IEEE 802.11n) includeknown techniques for coupling wireless devices (which might be mobilestations) to a computer network. In the IEEE 802.11 standard, wirelessdevices seek out and select “access points” (herein sometimes called“AP's”). Each wireless device associates itself with a particular AP,with which it communicates. Each mobile station determines from time totime if it has good communication with its associated AP, and whether itwould have better communication with a different AP. As a result of thisdetermination, mobile stations may associate with another AP.

Access points exhibit a known deficiency when servicing data flows fromdifferent mobile stations. Because multiple devices may operation on agiven frequency, data collisions occur when two or more mobile stationsattempt to transmit at the same time. Accordingly, wireless standardshave collision avoidance and correction mechanisms to reduce thenegative impact of data collisions and to recover from them when theyoccur. Generally, the collision avoidance systems involve a random delaytime such that each station waits a random amount of time beforeattempting to transmit. In most cases, this allows for one station totransmit first and not collide with the other station. In wirelessnetworks covering a wide area, collision avoidance systems are lessaffective because each mobile station may be too far away fromneighboring mobile stations to sense when the neighboring station istransmitting. Therefore, when two or more mobile stations transmit theyare unaware of the other station's transmissions and will not effectuatecollision avoidance procedures.

Additionally, because the IEEE 802.11 standards require backwardcompatibility, differing wireless devices may be connected to the accesspoints using different transmission speeds. Consequently slower devicesrequire more “air time” to transmit the same amount of information ascompared to newer, higher bandwidth devices. Since air time, bynecessity, must be shared among the differing wireless devices thatutilize the same access point, a slower wireless device causes a generalslowdown for other devices operating with the access point. Thisslowdown adversely impacts systems where the quality of service (QoS) isimportant such as digital voice systems. In digital voice systems,transmission latency may provide a degradation of service that isapparent to a listener.

SUMMARY

Disclosed herein is a communication system comprising one or morewireless stations (or mobile stations), programmed to await for anauthorizing signal (poll) to initiate wireless communications with anetwork controller or access point. The network controller maintainsidentification information in different queues, said queues based uponthe wireless station's activity. The wireless station identificationinformation is moved between the different queues in response towireless station activity, so the more active stations are maintained inone queue and polled more often, while less active stations aremaintained in a second queue and polled less often. Between polling,each mobile station aggregates data for the next opportunity totransmit.

Multi-polling may be employed such that more than a single station ispolled at a time. Polling is accomplished by polling one of the moreactive station along with a less active station. The less active stationis unlikely to transmit, so collisions are avoided to a certain degree.If a lesser active station becomes active, it is moved into the moreactive queue and consequently will be polled more often. This has theaffect of giving less active stations fewer opportunities to communicatewith the network controller than more active stations. Additionally,polling may be regulated according to either amount of data or theamount of airtime required to transmit.

Polling multiple stations may also be accomplished by polling loweractivity stations while simultaneously communicating data traffic withmore active stations having the affect of not simultaneously polling,but instead polling certain stations while passing data with others.

The construction and method of operation of the invention, however,together with additional objectives and advantages thereof will be bestunderstood from the following description of specific embodiments whenread in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a functional diagram of a wireless network.

FIG. 2 is a flowchart showing a modified time division multiple access(TDMA) protocol for a communications network.

FIG. 3 illustrates a wireless network system.

DESCRIPTION Generality of Invention

This application should be read in the most general possible form. Thisincludes, without limitation, the following:

References to specific techniques include alternative and more generaltechniques, especially when discussing aspects of the invention, or howthe invention might be made or used.

References to contemplated causes and effects for some implementationsdo not preclude other causes or effects that might occur in otherimplementations.

References to reasons for using particular techniques do not precludeother reasons or techniques, even if completely contrary, wherecircumstances would indicate that the stated reasons or techniques arenot as applicable.

Furthermore, the invention is not limited to the specifics of anyparticular embodiments and examples disclosed herein. Many othervariations are possible which remain within the content, scope andspirit of the invention, and these variations would become clear tothose skilled in the art after reading this application.

Lexicography

Read this application with the following terms and phrases in their mostgeneral form. The general meaning of each of these terms or phrases isillustrative, not in any way limiting.

The phrase “processing device” generally refers to an electronic devicecapable of being programmed to execute instructions. These instructionsmay be stored in memory for execution by the processor, or theprocessing device may be configured to execute instructions directly. Aprocessing device generally includes a form of input/output such thatthe results of the processing are made available for further processingor to perform a task in another stage of processing. A processing deviceis made operable by providing and or executing instructions.

The phrase “access point”, the term “AP”, and the like, generally referto devices capable of wireless communication with wireless devices andcapable of either wired or wireless communication with other devices. Insome embodiments, AP's communicate with external devices using a localnetwork. However, there is no particular requirement that AP's have anactual wired communication link; AP's might communicate entirelywirelessly.

The phrases “incoming message” and “received frame” generally refer to amessage packet or message frame sent by a wireless device or wirelessstation to an AP. In the preferred embodiment these phrases refer to aframe sent by a wireless station to an AP under 802.11 wirelesscommunication standards. The incoming message may be a unicast frame(intended for a single AP) or a multicast frame (intended for multipleAP's).

The phrases “outgoing message” and “transmit frame” generally refer to amessage packet or message frame being sent to a wireless device orwireless station from an AP. In the preferred embodiment these phrasesrefer to a frame sent by an access point to a wireless device under802.11 wireless communication standards. The outgoing message may be aunicast frame or a multicast frame.

The phrase “wireless communication” and the like, generally refers toradio frequency or other electromagnetic communication. In preferredembodiments, wireless communication includes a wireless communicationstandard such as IEEE 802.11a, 11b, 11g, or 11n. However, in the contextof the invention, there is no particular requirement that wirelesscommunication or a communication network must necessarily (1) use radiospectrum, (2) use electromagnetic communication, or even (3) be entirelyconfined to untethered communication coupling.

The phrases “wireless device”, “wireless station”, “mobile station” andthe like, generally refer to devices capable of wireless communicationwith AP's. In some embodiments, wireless devices implement a wirelesscommunication standard such as IEEE 802.11a, 11b, 11g, or 11n. However,in the context of the invention, there is no particular requirement (1)that this particular communication standard is used, e.g., the wirelesscommunication might be conducted according to a standard other than802.11, or even according to a an IEEE standard entirely, or (2) thatall wireless devices each use the same standard or even useinter-compatible communication standards.

The phrase “data flow” generally refers to a grouping of digitaltraffic. The grouping generally is identified by a combination ofheaders and footers indicating source address, destination address,source port, and destination port along with the transmitted data andother control signals. In effect, all traffic matching a specificcombination of these values is logically grouped together into a dataflow. A data flow can represent a single TCP connection between twocomputing devices. Data flows are generally characterized by both adownlink portion and an uplink portion. The uplink portion can becharacterized as an incoming message as described above, whereas thedownlink portion flows in the opposite direction.

The phrases “air time”, “on air time” or “airtime” generally refer to aduration of a specific transmission for a wireless network. Thisduration may be the time is takes to transmit an outgoing message or thetime it takes to receive an incoming message. The airtime may be actual,wherein the airtime is measured from a transceiver, or calculated basedon the size of the message and the expected broadcast rate.

System Elements

Specific examples of components and arrangements are described below tosimplify the present disclosure. These are, of course, merely examplesand are not intended to be limiting. In addition, the present disclosuremay repeat reference numerals and/or letters in the various examples.This repetition is for the purpose of simplicity and clarity and doesnot in itself dictate a relationship between the various embodimentsand/or configurations discussed.

FIG. 1 shows a functional diagram of a wireless network. The wirelessnetwork includes both fixed and mobile stations. A server 110 connectsto the network 112 for providing file access services. The network 112connects in turn to one or more access points 114. The access points 114provide wireless communications through links to one or more mobilestations (or wireless devices) 118 a-118 c. Each wireless device isconnected to the access point 114 according to the protocol inherent inthe design of the wireless device, for example 802.11 or others. Theprotocols may have different speeds or data rates for transmitting andreceiving data between the wireless device 118 and the access points114. During wireless operation the data rate may change to reduce theimpact of any interference or to account for other conditions.

In operation each wireless device 118 connects to the access point 114through its own protocol establishing the communication rate for thewireless network. The access point 114 is a processing device having amemory which may use both wireless communications of hard wiredcommunications as an input-output means. Once the communication rate isestablished, data from the server 110 is coupled to the wireless device118 through the network and the access point 114 allowing communicationsto occur.

Digital communications devices conventionally operate with a multi-layerconfiguration generally consisting of the Application, Presentation,Session, Transport, Network, Data Link, and Physical layers. A layer isa collection of related functions that provides services to the layerabove it and receives services from the layer below it. For example, alayer that provides error-free communications across a network providesthe path needed by applications above it, while it calls the next lowerlayer to send and receive packets that make up the contents of the path.

One having skill in the art will appreciate that the server 110 mayrepresent only one device of the type that may be connected to anetwork. Wide area networks such as the Internet may provide connectionsto a wide variety of devices and other networks, and communicationsbetween multiple mobile stations mat be effectuated through an APwithout the use of a server.

References in the specification to “one embodiment”, “an embodiment”,“an example embodiment”, etc., indicate that the embodiment describedmay include a particular feature, structure or characteristic, but everyembodiment may not necessarily include the particular feature, structureor characteristic. Moreover, such phrases are not necessarily referringto the same embodiment. Further, when a particular feature, structure orcharacteristic is described in connection with an embodiment, it issubmitted that it is within the knowledge of one of ordinary skill inthe art to effect such feature, structure or characteristic inconnection with other embodiments whether or not explicitly described.Parts of the description are presented using terminology commonlyemployed by those of ordinary skill in the art to convey the substanceof their work to others of ordinary skill in the art.

Polling

FIG. 2 is a flowchart showing a modified time division multiple access(TDMA) protocol for a communications network. TDMA is a channel accessmethod for shared medium networks that allows several users to share thesame frequency channel by dividing the signal into different time slots.The users transmit in rapid succession, one after the other, each usinga predetermined time slot. This allows multiple stations to share thesame transmission medium or radio frequency channel while using only apart of its channel capacity.

TDMA may be implemented with multiple mobile stations and an accesspoint wherein the AP acts as a network controller and polls periodicallyeach mobile station. In this implementation, the AP polls each stationallowing each mobile station an opportunity to respond. Mobile stationsdo not transmit until they have been polled by the network controller.

According to the current disclosure, two lists of stations aremaintained by the network controller. The lists are managed as a queuesuch that the network controller can cycle through each station in thelists for successive polling. Generally the first list (queue A)contains contact information for active stations, while the second list(queue B) contains contact information for inactive or reduced activitystations. Contact information may be any identification information usedto initiate polling such as a station ID. As each station is polled itis moved from the front of the queue to the rear of the queue.

At a flow marker 210 the method begins. At a step 212 the networkcontroller polls one station from queue A (active stations) andsubstantially simultaneously (or near in time) polls a second stationfrom queue B (inactive stations). Polling can be performed substantiallysimultaneously by encoding the polling signal to address both stations.After polling, the network controller waits a predetermined time for aresponse.

At a step 214, if a signal is received it is tested to see if it camefrom the station in queue B. If so, operation is transferred to a step216. At the step 216, the signal is processed by sending data, receivingdata or other operations as determined by the network system. Operationcontinues to a step 218 where the station is moved from the queue B tothe queue A, in essence moving the station from the inactive list to theactive list. Operation then proceeds to a step 220. At the step 220, thequeues are advanced so that different stations may be identified forpolling. From the step 220 operation proceeds to the step 212 where thenext enqueued stations are polled and the operation proceeds again.

Returning to the step 214, if the received signal is not from thestation in queue B, it is tested to see if the received signal is fromthe station in queue A. If it is, the process is transferred to a step226 for processing of the received signal from the station in queue A.The signal is processed by sending data, receiving data or otheroperations as determined by the network system. Operation then proceedsto a step 220 described above.

If a signal is not received from either the station in queue A or queueB, the operation moves to a step 224. At the step 224 the station fromqueue A is analyzed to test its activity and determine eligibility to bemoved from queue A to queue B. If the station in queue A has notresponded for a predetermined time, the station is moved from queue A toqueue B. The amount of time required for a response may be dynamicallycalculated. For example, a rolling average of polls and responses for aprevious time may be used to predict the behavior of the station inqueue A. Simpler methods of prediction may also be sued such as a countof non-responses to polling attempts. However the determination is made,if the station is queue A is determined to be unlikely to respond to animmediate polling, the station is moved to queue B at a step 228.

In operation the protocol of FIG. 2 operates to alleviate the problem ofoversubscribing because stations in queue A and queue B may be polled atdifferent rates. Queue A, containing the most active stations, is likelyto be shorter than queue B because queue B has the least activestations. The stations in queue A are polled more frequently because ofthe shorter queue. In the event of a collision, the most active stationswill be soon polled again whereas the least active stations, when polledagain, will likely be polled with a different station, enhancing theopportunity to connect to the network controller.

The stations having been recently polled are moved to the back of theirrespective queues. The inventors contemplate operating the queues on afirst in first out basis, however one having skill in the art willrecognize that different queuing protocols may be effectuated whileretaining the same spirit of the current disclosure.

Polling need not always be performed simultaneously. By way of example,an AP may establish a communications link with a wireless station suchthat data is being transferred between the AP and the wireless station.During transmissions of data from the AP (downlink), the AP can poll oneor more stations from the less active queue. In the event one of theless active stations has traffic, it may transmit an indication, thusallowing the station to be moved into the active station queue forfurther processing. While some collisions may occur, conventionalcollision correction schemes would allow for recovery.

Data Aggregation

According to the present disclosure, between polling times the mobilestation aggregates data to be transmitted so that when the mobilestation is polled it can send all aggregated data as a larger datapacket. The network controller may poll the mobile station to determinethe amount of data the mobile station has to transmit and allocate atransmission time for the mobile station. The transmission time may bebased on the amount of data or on the calculated transmission time ofthe data. This allows for the network controller to allocate time basedon the data rate currently available for the mobile station. Aggregationinto manageable “chunks” of data allow for the network controller toprioritize and facilitate data flows from differing mobile stations.

FIG. 3 illustrates a wireless network. The network has an access point(AP) 310 wirelessly coupled to a group of wireless stations 312-320.Each wireless station 312-320 has a coverage area 312 a-320 arepresented by a dotted line in the FIG. 3. The coverage area representsthe distance from the wireless station that the wireless station iscapable of communications. The distance is dependant on the wirelessstations transmission power, transmission frequency, atmospherics andother generally known radio frequency communication factors. Generallythe coverage area is circular, but obstacles may interfere with thisshape of the coverage area, and the antenna for each wireless stationmay be designed to shape the coverage area for a desired affect.

In the FIG. 3 the AP 310 has established wireless communications witheach wireless station 312-320. The stations 312-320 generally do notcommunicate with each other, even though some of their coverage areaoverlaps. For example, station 312 and station 320 are within eachothers coverage area, but communicate exclusively with the AP 310. Eachstation when not communicating with the AP 310 is aggregating data fromits respective electronic equipment (not shown). The wireless stations312-320 are receiving any signal transmitted from the AP 310, but unlessthe other wireless stations are within their respective coverage areas,the wireless station will not receive a signal from another wirelessstation. When the AP 310 transmits, each wireless station 312-320receives the signal, decodes it and determines if the signal is meantfor that wireless station. This may be accomplished by transmitting aunique query to the stations to inquire about any data traffic thestation has to transmit to the AP. According to one aspect of thedisclosure, the AP may query two or more stations simultaneously or inrapid succession. Once a signal is received by that station, and it isdetermined that the signal is meant for that particular station, thestation transmits a reply to the AP. The reply may indicate the amountof data to transmit, or that there is no data traffic to transmit.Alternatively, if there is no data to transmit, the station may forgotransmission.

The AP 310, when it receives a reply from a station, will signal to thatstation that it may begin to transmit data. The AP may signal apredetermined amount of time or data within which the wireless stationmust limit its transmission. The wireless station will buffer any datait cannot transmit within the predetermined amount of time and transmitit at the next available opportunity. This allows for the AP to functionas a network controller and dynamically control the data flow throughoutthe network. When used with the other techniques herein described, theAP may provide priority to certain wireless stations by maintaining aqueue of priority stations, thus increasing the quality of service forthat station. Additionally, the AP may reduce data collisions by varyingpolling rates and queue management.

The above illustration provides many different embodiments orembodiments for implementing different features of the invention.Specific embodiments of components and processes are described to helpclarify the invention. These are, of course, merely embodiments and arenot intended to limit the invention from that described in the claims.

Although the invention is illustrated and described herein as embodiedin one or more specific examples, it is nevertheless not intended to belimited to the details shown, since various modifications and structuralchanges may be made therein without departing from the spirit of theinvention and within the scope and range of equivalents of the claims.Accordingly, it is appropriate that the appended claims be construedbroadly and in a manner consistent with the scope of the invention, asset forth in the following claims.

What is claimed is:
 1. A system comprising: a network controlleroperable to: maintain wireless station identification information in anactive queue and an inactive queue; simultaneously poll, on the samefrequency, a station from the active queue and a station from theinactive queue, by encoding the polling signal to address both stations;test a received signal to determine if the received signal came from astation in the active queue or the inactive queue; calculate alikelihood of a station to respond to a future polling signal, saidcalculation including calculating the rolling average of prior responsetimes from the station and move the station to a different queue inresponse to said calculation, and allocate transmission time for thewireless stations in response to said polling.
 2. The system of claim 1wherein the network controller is an access point and the wirelessstation is a mobile station.
 3. The system of claim 1 wherein theresponse to said polling includes an indication of either an amount ofdata or an amount of airtime.
 4. The system of claim 1 wherein thenetwork controller is further operable to move identificationinformation between the different queues response to said polling. 5.The system of claim 1 wherein the mobile stations are further operableto aggregate data between polling.
 6. The system of claim 1 wherein thenetwork controller is further operable to poll a first wireless stationat substantially the same time as transmitting downlink data to a secondwireless station.
 7. The system of claim 1 wherein the response to saidpolling includes an indication of wireless station activity.
 8. A methodcomprising: in a data communications device, maintaining wirelessstation identification information in an active queue; maintainingwireless station identification information in an inactive queue;encoding a polling signal to address a plurality of stations, each ofsaid plurality of stations from a different queue; simultaneouslypolling, on substantially the same frequency, the plurality of wirelessstations using the polling signal; testing a received signal todetermine if the received signal came from a station in the active queueor the inactive queue; calculating a likelihood of a station to respondto a future polling signal, said calculating including calculating therolling average of prior response times from the station; moving thestation to a different queue in response to said calculating, andallocating transmission time for the wireless stations in response tosaid polling.
 9. The method of claim 8 wherein the data communicationsdevice is an access point and the wireless station is a mobile station.10. The method of claim 8 wherein the response to said polling includesan indication of either an amount of data or an amount of airtime. 11.The method of claim 8 wherein the data communications device is furtheroperable to move identification information between the different queuesresponse to said polling.
 12. The method of claim 8 wherein the mobilestations are further operable to aggregate data between polling.
 13. Themethod of claim 8 wherein the network controller is further operable topoll a first wireless station at substantially the same time astransmitting downlink data to a second wireless station.
 14. The methodof claim 8 wherein the response to said polling includes an indicationof wireless station activity.
 15. One or more processor readable storagedevices having non-transitory processor readable code embodied on saidprocessor readable storage devices, said processor readable code forprogramming one or more processors to perform a method comprising:maintaining wireless station identification information in an activequeue; maintaining wireless station identification information in aninactive queue; encoding a polling signal to address a plurality ofstations, each of said plurality of stations from a different queue;simultaneously polling, on substantially the same frequency, theplurality of wireless stations using the polling signal; testing areceived signal to determine if the received signal came from a stationin the active queue or the inactive queue; calculating a likelihood of astation to respond to a future polling signal, said calculatingincluding calculating the rolling average of prior response times fromthe station; moving the station to a different queue in response to saidcalculating, and allocating transmission time for the wireless stationsin response to said polling.
 16. The device of claim 15 wherein theresponse to said polling includes an indication of either an amount ofdata or an amount of airtime.
 17. The device of claim 15 wherein themethod further includes moving identification information between thedifferent queues response to said polling.
 18. The device of claim 15further including polling a first wireless station at substantially thesame time as transmitting downlink data to a second wireless station.19. The device of claim 15 wherein the response to said polling includesan indication of wireless station activity.